Thread replenishing mechanism for lock stitch sewing machines



Dec. 29, 1964 W. J. EDWARDS THREAD REPLENISHING MECHANISM FOR LOCK STITCH SEWING MACHINES Filed May 14, 1963 2 Sheets-Sheet l A?, @Ll-J TORNE Y Dec. 29, 1964 J. EDWARDS 3,163,137 THREAD REPLENISHING MECHANISM FOR A LOCK STITCH SEWING MACHINES Filed May 14, 1963 2 Sheets-Sheet 2 QQ. 45 @Q2 44 Fig. 2. 6| i ff 47 INVENTOR. 60 46 WILL/AM J. EDWARDS WITNESS 63 62 Wdo TORNE Y United States Patent Olice Patented Dec. 29., 1 964 3,163,137 THREAD REPLENISHING MECHANESM FR LOCK STITCH SEWING MACHENES William J. Edwards, Denville, NJ., assignor to The Singer Company, a corporation of New Eersey Filed May 14, 1963, Ser. No. 280,388 6 Claims. (Cl. 112-181) This invention relates lto lock stitch sewing machines of the type which under or locking thread may be replenished on the bohbin in place in the loop taker while the loop taker partakes of regular motion as is required for the formation of lock stitches, and more particularly, to a novel and improved mechanism whereby the machine operator may at will initiate and control the thread replenishing operation.

It is an object of this invention to provide a simple and dependable mechanism for replenishing thread on a bobbin in place in the loop taker of a lock stitch sewing machine automatically in response to depression by a sewing machine operator of a push button on the machine frame.

Another object of this invention is to provide a novel latch means for maintaining the bobbin thread replenishing control push button depressed so as not to require the continued application of force by the operator to hold the push button depressed when winding a considerable amount of bobbin thread.

It is also an object of this invention to provide a novel latch throw-out larrangement rendered effective to p-revent or interrupt bobbin thread replenishment in the event that other mechanisms of the sewing machine are not in position favorable for bobbin thread replenishment.

With the above and additional objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawing of a preferred embodiment in which:

FIG. 1 is a vertical cross sectional View of a sewing machine having this invention applied thereto.

FIG. 2 -is a cross sectional view taken substantially along line 2-2 of FIG. 1.

FIG. 3 is an enlarged vertical cross sectional View of the thread replenishing control push button and a fragment of the sewing machine bed as illustrated in FIG. l but showing the push button l-atched in depressed position, and

FIG. 4 is an enlarged horizontal cross sectional view taken substantially along line 4-4 of FIG. l, illustrating the latch throw-out arrangement of this invention.

Referring particularly to FIGS. 1 and 2 the sewing machine to which this invention is applied includes a frame comprising a bed 11 from which rises a. standard 12 supporting a bracket arm 13 overhanging the bed. Iournalled for endwise reciprocatory motion in the bracket arm is a needle bar 14 to which is secured la thread carrying needle 15 which cooperates, in the formation of lock stitches, with a loop taker, indicated generally at 16, which is journaled in the bed. The needle and loop taker remain permanently interconnected for opera? tion in timed relation as is required for the formation of lock stitches by means of the drive connections including a main shaft 17 journaled in the bracket arm and drivingly connected by means of a crank 18 and a connecting link 19 to the needle bar. By means of meshing gear sets 28, 21 and 22, the main shaft 17 is drivingly connected by way of a standard shaft 23 and a bed shaft 24 to a loop taker shaft 25 on which the loop taker is secured. An electric motor 26 which may be enclosed within the standardof the machine drives the sewing machine main shaft 17 by way of a worm 27 and a worm wheel 28 connectionny The crank 18 on the main shaft which drives the needle bar also imparts oscillatory motion to the needle thread take up lever 29 which is constrained in the bracket arm by means of an anchor link 30.

The loop taker 16, as illustrated in FIGS. 1 and 2, may be constructed in accordance with the details disclosed in the United States patent application of S. I. Ketterer, Serial No. 133,896, led Aug. 25, 1961, now Patent No. 3,115,855, to which reference may be had. For an understanding of this invention it is sufficient to understand that the loop taker includes a cup shaped rotary body portion 46 in which is journaled a bobbin case 41. A thread carrying bobbin 42 is journaled rotatably in the bobbin case and when the bobbin thread is to be replenished the bobbin is ladapted to be engaged by a bobbin Winding member 43 fast on a rod 44 in an axial bore 4S in the loop taker shaft. A collar 46 fast on the rod 44 is formed with a tang 47 accommodated in an aperture 48 in the gear 22 on the loop taker shaft so as to lock the bobbin winding member for rotation with the loop taker. The boboin winding member, however, may be shifted axially of the loop taker into and out oi' engagement with the bobbin, and the bobbin winding member includes a drive pin 49 engageable in a notch Sil formed in the underside of the bobbin so that the bobbin will be positively driven when the bo-bbin winding member is shifted into engagement therewith.

When ythe bobbin winding member 43 is shifted axially of the loop taker into engagement with the bobbin, operation of the sewing machine will serve to wind on the bobbin a supply of thread from the thread carrying needle. A detailed description of this bobbin thread replenishing operation is contained in the above referenced cti-pending United States patent appli-cation Serial No'. 133,896. The mechanism of this invention for controlling the operation of lthe bobbin thread replenishing mechanism comprises a bobbin thread replenishing lever 60 fulcrumed on a shouldered screw 61 beneath the bed and having a leaf spring 62 secured thereto, as by screws 63, which leaf spring is secured to the lower extremity of the rod 44 by a clamp nut 64.

At the opposite extremity of the bobbin thread replenishing lever from the connect-ion with the rod 44, a push rod 65 is secured to vthe lever 6) by means of a flexible leaf spring 66. The push rod 65 protrudes through an aperture 67 in the sewing machine bed 11 so that an operator intluenced push button 68 formed on the upper extremity of the push rod will be accessible to a sewing machine operato-r. The `spring 66 by which the push rod is secured to Ithe bobbin thread replenishing lever serves as both a pivotal connection of the push rod with the lever 60 and also to bias the push rod laterally against one side of the aperture 67. The aperture 67 in the sewing machine may be hushed with a wear insert 69.

The juncture of the push button 68 with the push rod 65 defines a shoulder 70 on the push rod 65 which cooperates with the under surface 71 of the wear insert 69, or withthe under surface of the bed 11 adjacent to the aperture 67 if no Wear insert is used, to provide a latch means for constraining the push rod in a depressed position in which the bobbin thread replenishing lever will be turned to raise the bobbin winding member into engagement with thelbobbin, thus to condition the ma- 70 for terminating the bobbin thread replenishing operaby the arrow B in FlG. 3.

tion, the operator need only appli7 force to the push button 68 atop the push rod in the direction indicated The bobbin thread replenishing lever 6G is biased into a position in which the bobbin winding Vmember is carried ont of engagement with the bobbin by means of a spring 'FS secured to the lever d@ andthe under side of the bed ll. The bobbin thread rcplenishing lever is also tted with a stop member 76 (FIG. l) preferably having a cushioned cap 77 which abuts beneath `the bed to limit the swinging motion of the lever 60 in response to the spring 75.

The sewing machine illustrated in Fl-GS. l and 2 includes a work feeding mechanism of the drop feed variety including a feed dog dll which is opposed by a spring loaded presser foot Sl carried on a presser bar 82 slidably arranged in the bracket arm. The presser bar is fitted with a block 83 within the bracket arm which overlies a cam portion S4 or a presser lifting lever 85 and fulcrumed in the bracket arm by `which the presser foot may be raised and lovvered into and out of a position opposing the feed dog. With the control mechanisms for-replenishment of thread on the bobbin of this invention, it is desirable that the presser foot be raised during bobbin thread replenishing operation. Raising of the presser foot Will not only render the feed dog inellective to advance the work but will also operate a tension releasing lever d which works olf the presser lifting lever 85 to release the tension imposed on the needle thread lby a thread tensioning device S7.

ln order to prevent initiation of bobbin thread replenishment when the presser toot is lowered, and to effect a termination of bobbin thread replenishment in 'die event that the presser foot is lowered while the bobbin is being wound, a cable 9i! is secured at one extremity by a fastening yscrew 9i to the block S3 on the presser bar. The cable extends through the bracket arm and standard through a cable guide 92 adjustably secured in the bed and is secured at the opposite extremity to one arm 93 of a latch release lever $42 fulcrumed at the shouldered screw SS beneath the bed. The latch release lever 94 is formed with a linger 96 movable, in response to lowering the presserfoot, laterally into engagement with the push rod 65 so as to apply to the push rod a force in the direction Aof the arrow B, as illustrated in Pi. 3, which will substantially center the push rod in the aperture 67 or in the wear insert 69 and release the latch surfaces 7i?, 7l to terminate bobbin thread replenishment in the event that the presser foot is lowered.

The push rod 65 is formed with a lateral recess or notch lll@ adapted to accommodate the linger 96 on the latch'release lever 94 when the bobbin thread replenishing mechanism is in the inoperative position illustrated in FlG. 1. When the presser foot is lowered during sewing, therefore, the finger 96 will be shifted into the .notch 160 in the push rod 65 and will prevent depression of the push button to initiate bobbin thread replenishment.

Having thus set forth the nature of this invention, what is claimed herein is.' Y

1. In a sewing machine havin'J a frame, a thread carrying needle and a circularly moving loop taker carried in said frame vand. operatively connected for interrelated movements as are required for the formation of lock stitches, a thread carrying bobbin journaled in said loop taker and a bobbin Winding member interlocked for circular movement with said loop taker and shiftable relatively to said loop taker into and out of a position 'effective to wind thread from said thread carrying needle onto said bobbin, mechanism for controlling the winding of thread on said bobbin comprising a lever fulcruined in said sewing machine frame, bearing means on said circularly moving bobbin lwinding member and on Y said lever constraining said bobbin Winding member for axial movement in response to turning movement of said lever aboutsaid fulcrum, interengaging stop means on said leverY and on said sewing machine frame limiting lll) turning movement of said lever in that direction shifting said bobbin winding member out of engagement with said bobbin, spring means biasing said lever toward engagement of said stop means, and a push rod secured to said lever within said sewing machine frame and extending outwardlj,I through a clearance aperture in said sewing machine frame for operator influenced turning of said lever in opposition to said spring means.

2. ln a sewing machine having a casing, a thread carrying endivise reciprocatory needle supported in said casing, a work presser device carried on said casing, mechanism on said casing for lifting said work presser device to an inoperative position and for lowering said Work presser device to eilective position, a circular-ly moving loop taker iournaled in said casing and actuated in timed relation with said needle, and a thread carry'- ing bobbin journaled in said loop taker, means for replcnishing thread on said bobbin in place in said loop taker comprising a bobbin Winding member interlocked for circular motion with said loop taker and sliittably supported in said loop taker for movement relatively thereto into and ont of engagement with said bobbin` a lever ulcrunied within said sewing machine casing and operatively connected to said bobbiri winding member to eliect shifting movement thereto, a push rod connected to said lever, said sewing machine casing being formed with an aperture slidably accommodating said push rod, latch means on said push rod on said sewing iriachine easing for constraining said lever in a position maintaining said bobbin winding member into engagement with said bobbin, and release mechanism for said latch means operatively connected to operate said presser device and effective to release said latch means when said work presser device occupies a lowered position.

3. ln a sewing machine having a casing, a thread carrying endwise reciprocatory needle supported in said casing, a work presser device carried on said casing, mechanism on said casing for lifting said work presser device to an inoperative position and for lowering said work presser device to effective position, a circularly moving loop taker iouriialcd in said casing and actuated in timed relation with said needle, and a thread carrying boboin journaled in said loop taker, means for replenishing thread on said bobbin in place in said loop taker cornprising a bobbin winding member interlocked for circular motion with said loop taker and shiftably supported in said loop taker for axial movement relatively thereto into and out of engagement with said bobbin, a lever fulcruined within said sewing machine casing and operativelyI connected to said bobbin winding member to cilect axial shitting movement thereto, an endwise shiftable push rod extending through said sewing machine casing and connected to said lever, a lirst latch means on said push rod and on said casing for constraining said push rod in an endwise position maintaining said bobbin winding member in said operative posteri, a second latch means on sad push rod and on said casing for constraining said push rod in an endvvise position maintaining said bobbin winding member in an inoperative position, and latch release mechanism connected to said work presser device effective to release said rst latch means when said presser device occupies a lowered position and effective to release said second latch means when said presser device occupies a lifted position.

4. ln a sewing machine having a casing, a thread carrying endvvise reciprocatory needle supported in said casing, a Work presser device carried on said casing, mechanism on said casi-ng for lifting said work presser device to an inoperative position and for lowering said work presser devce to effective position, a circularly moving loop taker journaled in said casing and actuated in timed relation with said needle, and a thread carrying bobbin iournaled in said loop taker, means for replenishing thread on said bobbin in said loop taker comprising a bobbin winding member interlocked for circular .motion with said loop taker and shiftably supported in said loop taker for axial movement relatively thereto into and out of engagement with said bobbin, a lever fulcrumed within said sewing machine casing and operatively connected to said bobbin winding member to eiect axial shifting movement thereto, a push rod pivotally connected to said lever, said sewing machine casing being formed with an aperture loosely accommodating said push rod therethrough, spring means biasing said push rod laterally against one side of said aperture, interengaging latch means on said push rod and on said casing adjacent to said aperture effective when said push rod is depressed for constraining said lever in a position maintaining said bobbin winding member into engagement with said bobbin, a latch release member shiftably supported on said casing for movement laterally into engagement with said push rod, a connection element between said work presser device and said latch release member elective when said work presser device occupies a lowered position to substantially center said push rod in said casing aperture thereby disengaging said latch means.

`5. A device as set forth in claim 4 in which said push rod is formed with a notch accommodating said latch release member when said push rod is released and said work presser device occupies a lowered position to prevent depression of said push rod while said work presser device occupies a lowered position.

6. A device as set forth in claim 4 in which said latch release member comprises a latch release lever fulcrumed on said sewing machine casing and in which said connection element comprises a flexible cable secured at one extremity to saidilatch release lever and secured at the other extremity to said work presser device.

References Cited in the file of this patent UNTTED STATES PATENTS 1,794,255 Stephenson Feb. 24, 1931 2,991,572 Swenson July 11, 1961 3,045,370 Foster July 24, 1962 3,103,189 Ketterer Sept. 10, 1963 

1. IN A SEWING MACHINE HAVING A FRAME, A THREAD CARRYING NEEDLE AND A CIRCULARLY MOVING LOOP TAKER CARRIED IN SAID FRAME AND OPERATIVELY CONNECTED FOR INTERRELATED MOVEMENTS AS ARE REQUIRED FOR THE FORMATION OF LOCK STITCHES, A THREAD CARRYING BOBBIN JOURNALED IN SAID LOOP TAKER AND A BOBBIN WINDING MEMBER INTERLOCKED FOR CIRCULAR MOVEMENT WITH SAID LOOP TAKER AND SHIFTABLE RELATIVELY TO SAID LOOP TAKER INTO AND OUT OF A POSITION EFFECTIVE TO WIND THREAD FROM SAID THREAD CARRYING NEEDLE ONTO SAID BOBBIN, MECHANISM FOR CONTROLLING THE WINDING OF THREAD ON SAID BOBBIN COMPRISING A LEVER FULCRUMED IN SAID SEWING MACHINE FRAME, BEARING MEANS ON SAID CIRCULARLY MOVING BOBBIN WINDING MEMBER AND ON SID LEVER CONSTRAINING SAID BOBBIN WINDING MEMBER FOR AXIAL MOVEMENT IN RESPONE TO TURNING MOVEMENT OF SAID LEVER ABOUT SAID FULCRUM, INTERENGAGING STOP MEANS ON SAID LEVER AND ON SAID SEWING MACHINE FRAME LIMITING TURNING MOVEMENT OF SAID LEVER IN THAT DIRECTION SHIFTING SAID BOBBIN WINDING MEMBER OUT OF ENGAGEMENT WITH SAID BOBBIN, SPRING MEANS BIASING SAID LEVER TOWARD ENGAGEMENT OF SAID STOP MEANS, AND A PUSH ROD SECURED TO SAID LEVER WITHIN SAID SEWING MACHINE FRAME AND EXTENDING OUTWARDLY THROUGH A CLEARANCE APERTURE IN SAID SEWING MACHINE FRAME FOR OPERATOR INFLUENCED TURNING OF SAID LEVER IN OPPOSITION TO SAID SPRING MEANS. 